The present invention relates to equipment for use in testing leakage in pressure containing vessels or fluid lines, and, in particular, a control valve assembly with interface and microprocessor control for use in leak detection systems.
Manufacturers of hydraulic, pneumatic, and containment equipment customarily test the fluid integrity of their components to ensure safe operation in the field. Standards are generally prescribed for leakage rates at test pressures and times correlated to the desired component specifications.
Currently, leak detection systems are an assembly of separate components housed in portable test units. Using a myriad of valves and pneumatic lines a component to be tested is attached to the test unit and independent valves are sequenced to route pressurized fluid, customarily air, to the component, which is then isolated. The leakage rate at the component is then measured and a part accepted or rejected based thereon. The multiple valves and lines may be integrated into a portable test stand for on-site testing. Nonetheless, the pneumatic system is expansive and cumbersome, with each element posing the potential for associated malfunction and leaks. Further, automation of a testing protocol is difficult because of the independent relationship of the components. Where varying test pressures are required for other components, the system must be retrofitted for each such use.
For example, the leak detection apparatus as disclosed in U.S. Pat. No. 5,898,105 to Owens references a manually operated systems wherein the testing procedures is controlled by plural manual valves and associated conduit occasioning the aforementioned problems and limitations.
Similarly, the hydrostatic testing apparatus as disclosed in U.S. Pat. No. 3,577,768 to Aprill provides a portable unit comprised of a plurality of independent valves and associated lines for conducting testing on equipment and fluid lines. The valves are manually sequenced for isolating test components from a single pressure source. U.S. Pat. No. 5,440,918 to Oster also discloses a testing apparatus wherein a plurality of conventional valving and measuring components are individually fluidly connected in portable
Remotely controlled leak detection systems, such as disclosed in U.S. Pat. No. 5,557,965 to Fiechtner, have been proposed for monitoring underground liquid supplies. Such systems, however, also rely on an assembly of separate lines and valves. A similar system is disclosed in U.S. Pat. No. 5,046,519 to Stenstrom et al. US. Pat. No. 5,072,621 to Hassemann.
U.S. Pat. No. 5,540,083 to Sato et al. discloses remotely controlled electromagnetically operated valves for measuring leakage in vessels and parts. Separate valve and hydraulic lines are required.
In an effort to overcome the foregoing limitations, it would be desirable to provided a portable leakage detection system for testing the fluid integrity of fluid systems and components that includes integrated valving and porting within a compact envelope for automatically controlling a variable testing protocol. The leak detector includes a valve block having internal porting selectively controlled by four identical and unique pneumatic poppet valves for pressurizing the test part, isolating the test part for determining leakage rates with pressure and flow sensors communicating with the porting, and exhausting the test line upon completion of the leakage test. The poppet valves engage valve seats incorporated within the porting. The poppet valves are actuated by pilot valve pressure acting on a pilot piston to effect closure of the valve. The sensors interface with a microprocessor for comparing measurements with the test protocol and indicate pass or fail performance. Upon removal of the pilot valve pressure, the resident pressure in the porting shifts the valve to the open position. The leak detector includes plural inlets for accommodating variable pressure protocols. The leak detector thus eliminates the need for external fluid connections and conduits between the various detector components, eliminates the need for two-way valving actuation, and provides for connection with external test units with a single, easy to install, pneumatic line.